Process of concentrating ores.



ROBERT a. HALL, ors'r. LOUIS, MISS'O'UIRI.

PROCESS OF CONCERT-RATING OBES.

No Drawing.

To all whom it may concern:

Be it known that I, ROBERT Gr. HALL, a citizen of the United States, residing at St. Louis, State of Missouri, have invented an 5 Improvement in Processes of Concentrating Ores, of which the following is a specification, I .The processes hitherto used for extracting zinc and lead from com lex ores, es-

pecially those containing smal amounts of other valuable metals, as copper, sllver and gold, have generally been varied to suit the? character of each ore, andhave almost invariably resulted in a' great loss of the metals. v

The customary methods have been Physical.

ore. This has generally resulted in the pro duction of concentrates of the several metals l more orless separated, each containing an amount of some or all of theoth'er vialuablemetals which in this form. became lost, as, for example, small amounts of lead,-silver.

and copper in zinc concentrates, or of zinc in the concentrate of the other metals. Besides this there generally result certain no more value in this form.

Electm'oal.

difference either existing, or. that-may be 1' produced, in the electrical ormagnetic 'properties of; the various metallic mineral constitu'ents', and it. does'nqt in most'cases give clean products',' or complete' separation of give according to its various properties.

)h'emicail methods of seperation are based cuts in particular solvents, as,"f0r example,

zinc may be dissolved from acarbonate ore,

or from an ore either naturally or. artifieally'oxidized, and in case of the use of sulifurther that other meta s, such as copper. are

mixed products [further inseparable, and of I r the' same in aspecially designed; furnace,

This method of separation is based on athe minerals, but only such as eachore may 'furie acid-as solvent, 'any lead present will remainbeindinsoluble. The disadvantagesof this method are that fall th'eizinc in such ones ma, not 'be com lowly-soluble, and.

Speeiflcation of Letteril'atent. Patented $0, Application filed September 15, 1916. Serial Ho. 180,896. j

tions of the acid.- 01:, the meta'l constituentu' of an ore may be converted intolchlorid s, S9,!-

proposed. by ,Malm and others butin' case there still remains the difficulty of the separationbf the metallic chloride.

Many other methods of; separation have;

been proposed, .aa, fqr exam le, selective flotation, and .various'oth'ers, ut in most, if not all, cases, the separation isfnot absm lute, and the losses-"of byproducts or between-products are heavy.

In addition to the above, certain furnace methods have been used, as, forexampl Bartletts blast furnace, whereby themixell ores are charged into-a special type of blast furnace, and the zinc and lead with some of the silver are volatilized, while the copper -7 method of operation involves high losses of made in such blast furnace is certain to.-contain large quantities of both zinc and lead.

.Other inventorsfagfor example, Pa pe, propose the roastln of such ores w ere necessary, ;m1x1ng 0 same with reducing material, as-finely ground coke, briqueting of the resulting: mixture, and smelt ng of such 'asone of theWetherill-ty e, for the volatiliz'ingof the zinc and Tea The'ohjection tothis methorljs chiefly its high cost, and complexity. v ,',D esgratz', in his Patent #1 072,209, to-

' and the remaining silver and gold are recovered as a-ma'tte, Jtyisknown that this poses, first, reducing such ores o a liqui ';or

slag condition, then reactin'g on such slag wlth lime and areducing 'orlcarhonac eous.

materiahthus volatilizing, all "volatile si1b' stances,

My newly-invented profess differs from the above in that the .oxidizedgnixed ores,

or in thecase' of. sulfids, the desulfurized or partially desu'lfurized ,oresare mi'xed' with. the propenquantity .of reducing mate rial, and without further treatment" are charged directly into a 'reverberatory fur-; nace, andthere submitted 'to the heat' ,of

such fur'nace so that till the zinc and all thethe productsof com stion' in" as easily recover'able forms, All of the'ooiaper and gold, 't0gether1vv th fl ej greater part of thesilver.

'1ead, together with such ther reducible A volatile metals as may be present, are ex- ,pelled'iro'm the charge and carried out with I 85 tile reduction material.

cess of the quantity necessary to form a slag,

a customary flux in the smelting ofmost ores of the non-ferrous metals. For ex- -roasted so much sulfur may remain present .5 as maybe most desirable to form a matte of I the grade 'desired. In such case, the sulfids of'zinc and lead will be decomposed according to the reaction The reactions involved in the reduction of the oxids of zinc and lead by means of carbon are of course those commonly in.- volved in the reduction by means of can na'ceous material, Furthermore there may used in this reaction not only the solid and non-volati e forms of carbon, as coke, etc., but also those forms containing volatile constituents, as, for instance, the lower grades of bituminous coal and other waste material which may contain sutlicient amounts of fixed carbon or other non-vola- In this case the volatile combustible -material from the charge, as well as the carbon monoxid resulting from the reduction of the metallic oxid will burn within the furnace and on v 40 thesurface of the charge, an oxiding atmosphere being maintained in the furnace, and thus give valuable aid in the fusioh of the charge. By the above described method of smelting the mixed and complex ores I am able to handle directly all oxidized, and, by .a. partial'preliminary roast, -as, "for example, to

five to ten per cent. of'sulfur', all'sulfid ores without direct concentration, and without briqueting, forming directly the following products Waste Wttem'al in the iorm-0f slay.l5y

' the blast furnace method of smelting much care-has to be takenwitth the composition of this slag, as slags of certain composition, as,

forexamp'lc, those containing considerable quantities of ferrous oxid, will carry off 'large quantities of valuable zinc, which must be removcds-in subsequent operations, 'and at "considerable "expense? I am able by the ahovenmethod to make slags' of exceedingly variable Compositio'nin silica, ferrous oxid and linr'e which'are the principal waste ma-' erialsirof the ores in question, and at all tiu1e's to get proper and commercially clean cadmium, a ntimony, etc.

1,27e,oas

slags, ractically free from lead, zinc, eopper, si ver and g 1d.

Matter-The separation of the matte from the slag by this method of smelting is remarkably clean, for the reason that the matte formed may be of ample quantity, and in entire control of the operator, so that there is a continuous matte fall or formation to carry down the precious metals and the copper of the ore, and this. matte is of such a nature that the melting point low and the specific gravity is high, since ample, in the caseof a sulfid ore partially t IBIB lS IIO zinc sulfid present to raise the melting point and lower the specific gravity. Hence there is at all times good separation of. this matte from the waste material or slag, and ther'ecovery of the values is thereby Fpromotcd.

mm, or 'UOZdM-liZd material.--The material ,volatilized from the charge is of course immediately reoxidized by the atmosphere of the furnace, and carried along with the waste gases through waste heat boilers, or such cooling devices as may be necessary bee. fore recovery of the values in settlin cham- 90. hers, filter-bags, or other methods 0% recov- -,j cry. This fume will contain! all of the 'zinc and lead as oxids, or to some extent as sulfates, together with some small quantity of the silver, with such other small amounts of reducible metals as may under the conditions of-the furnace be volatile, as, for example,

The subsequent treatment of the valuable products will of course, depend on economic conditions. 'lhus the matte formed if-low 1 in grade of copper, gold or silver, or all three may be sent back through the same cycle as the ore, partially roasted and again charged into the furnace in the manner usual in lflfi ordinary methods of smeltin or it may be smelted directly or converte by the Manhees process to metallic copper. The re? covered .oxids maybe made use of 'ther directly as'a pigment, or the metals may be separated and recovered. I i y The use of the. reverberatory furnace in themanner above described for the direct smeltin of the complex ores above mentioned 1s a distinct advance and improvement over any method now in use. I do 0t claim any particular design or type of reverberatory furnace, but findi that the reaction can be carried out in alniost anytype of' reverberatory furnace, but may be specially well carried out bythe methodknown as side chargin whereby the charge prepared as'above escribed, is fed in along the sides of the furnace in small quantitiesand at frequent intervals, thus giving a. better.125 opportunity for the release of the volatile constituents. I l claim't-r "1. Thepro'cess of concentrating ores which consists in mixing oxidized ores containing 130 6 is-the beratory atilizingthe zinc and lead, and concentrat-' ing the other valuable metals as copper, silver elixiiinatingfthe waste material as a slag in a molten condition, free from the valuable metals of the charge.

2. The process otconcentrating ores, which consists in partially rpastin ore containing zinc, lead, and other iilua le metals, then mixing with the roasted ore a reducing material, the chargepontaining sulfur in the and gold, in the form of a matte, and

form of sulfid in amount suflicient to form a matte, and without further treatment smb- 1ect1n the same to the heat of a reverberatory urnace, thereby reducing and volatil- 'izing the zinc and lead, and. concentrating the'other valuable metals as copper, silver and gold in the form of a matte, and eliminating the waste material as a slag in a molten condition, freefrom the valuable metals of the charge.

'Inwtestimonywhereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

ROBERT G. HALL.-

Witnesses:

C. A. GRISHAM, F. S. WOQDBURN. 

